This invention relates to stain removal and stain treatment.
Products containing iodine or iodophors (complexes of iodine with a suitable carrier) are widely used in hospitals, clinics, nursing homes and other health care facilities. These products can quickly reduce microbial populations on skin, gums, and other tissues or surfaces. Unfortunately, when iodine- or iodophor-containing products are spilled or otherwise unintentionally contact surfaces such as tile floors, they can cause semi-permanent dark yellow or brown stains. These stains can be very difficult to remove using traditional cleaning and laundering techniques, and are especially difficult to remove from floor tiles. For example, when iodophors formed from a complex of iodine and polyvinylpyrrolidonc are spilled on vinyl composite tiles coated with a typical floor finish, both the finish and tiles may stain. Removal of such stains may require recoating the floor or even replacing the stained tiles. This can require substantial time and expenditure.
U.S. Pat. No. 5,385,604 describes a germicide-resistant floor polish. U.S. Pat. Nos. 4,828,569, 5,522,580, 5,669,937, 6,309,471 describe various cleaners for iodine or iodophor stains. Iodine or iodophor stains can also be removed by scrubbing the stain with a paste or solution of sodium thiosulfate.
Iodine and iodophor stains indicate that spillage or other mistakes may have taken place, are highly visible, and may remind viewers of blood or other bodily fluids. Accordingly, such stains are very undesirable in a health care facility.
The present invention provides, in one aspect, a method for reducing the visual impact of an iodine or iodophor stain comprising applying to the stain sufficient starch to impart a bluer coloration to and thereby mask the stain. The masked stain can be left as is until further cleaning or other surface repair or replacement can take place. The masked stain may instead or also be subjected to the action of a suitable decolorizing agent.
In another aspect, the invention provides a surface cleaning composition comprising detergent, starch and a reducing agent having a redox potential sufficient to decolorize an iodine or iodophor stain.
In yet another aspect, the invention provides a floor optionally bearing a floor finish coating, an iodine or iodophor stain on the floor or floor finish coating, and a further coating containing sufficient starch to impart a bluer coloration to the stain.
The invention can minimize the visual impact of an iodine or iodophor stain until the stain can be removed or decolorized. The starch reacts with triiodide anion in the stain to change the stain coloration from a yellowish hue (e.g., yellow-white, yellow or brown) towards a bluer hue (e.g., white, blue-white, blue or even dark blue). The shift in stain coloration is perceived by the human eye as making the stained surface cleaner in somewhat the same way the human eye perceives fabric treated with a fabric bluing agent as being cleaner.
In this application, iodine and iodophor will (unless the context requires otherwise) collectively be referred to as xe2x80x9ciodinexe2x80x9d.
In this application, a change in stain coloration from a yellowish hue towards a bluer hue will be referred to as xe2x80x9cmaskingxe2x80x9d. For a normal viewer, the thus-masked stain typically will be much less objectionable than the original stain. This will be so even if the masking reaction makes the stain dark blue, because the shift to a bluer coloration will also be perceived as making the stained surface cleaner.
The invention can be used to mask stains caused by a wide variety of iodine-containing products. Typical iodine-containing products include tincture of iodine and Lugol""s solution. The invention has particular utility for masking stains caused by iodophor-containing products. Iodophors are complexes of iodine with polymers such as polyvinyl pyrrolidone or polyethylene glycol, or complexes of iodine with a suitable surfactant. Iodine complexes with polyvinylpyrrolidone are especially widely-used and are generally known as povidone-iodine. Suitable commercially available povidone-iodine products include ALPHADINE(trademark) solution, ointment, powder and scrub foam (all commercially available from Ecolab Inc.) and BETADINE(trademark) antibiotics and microbicides (all commercially available from Purdue Pharma LP).
The invention can also be used to mask other problematic reducible stains that may be encountered, particularly those arising from the use of colored dyes in laboratories and certain food soils in cafeterias.
Starch for use in the invention can be obtained from a variety of sources such as rice, wheat, corn, potatoes, and the like. Depending in part on factors such as the molecular weight of the starch from such source and upon the desired degree of solubility, the starch can be used as is or hydrolyzed or emulsified as desired. Preferably the starch is hydrolyzed. Hydrolysis can be conveniently be accomplished by cooking the starch under appropriate conditions, using for example a pressure vessel and temperatures of about 100 to about 130xc2x0 C. Starch can also be hydrolyzed using other techniques that will be familiar to those skilled in the art, for example by using a suitable enzyme.
In one aspect of the invention, starch is applied to an iodine stain in the form of a solution or suspension in a suitable solvent (e.g., water), without other active ingredients. This permits masking of the stain until such time as permanent stain removal or repair of the stained surface can be carried out. Such removal or replacement may take place hours later (e.g., four hours later or longer if desired), at a suitably convenient time such as after the close of a business or after departure of patients or other personnel.
In another aspect of the invention, starch is applied to an iodine stain in the presence of a reducing agent having a redox potential sufficient to decolorize an iodine or iodophor stain. This masks the stain while is being decolorized. Preferred redox potentials for the reducing agent range from +0.558 to xe2x88x924.00 volts for the oxidative half-reaction at 25xc2x0 C., using redox potentials such as those shown in, e.g., Lange""s Handbook of Chemistry, 12th edition, pages 6-2 through 6-21, McGraw Hill (1979). Particularly preferred reducing agents include sulfites, hydrosulfites, nitrites, hydronitrites, phosphites and hydrophosphites, with sulfites being most preferred. A preferred amount of reducing agent is about 1 to about 10 weight percent of the solution or suspension, more preferably about 1 to about 4 weight percent and most preferably about 1 to about 3 weight percent.
The starch can also be applied to a surface that already contains a reducing agent that can decolorize the stain, as described in copending application Ser. No. 10/293,798 entitled STAIN RESISTANT COATING COMPOSITION, filed even date herewith and incorporated herein by reference in its entirety. In a preferred aspect of this copending application, a floor finish or sealer containing a reducing agent that can decolorize iodine stains is applied to a floor as one or more floor finish coats. While such a finish or sealer can provide an effective level of eventual stain control or elimination, a certain amount of time is required for decolorization to take place. The present invention can mask the stain during such decolorization.
In yet another aspect of the invention, starch is combined with a coating composition (e.g., a floor finish or other curable or hardenable film-forming composition) and then applied to a surface. The resulting coated surface can mask stains caused by iodine-containing products without application of a separate starch-containing composition to the stain. In a preferred embodiment, the coating composition also contains a reducing agent such as is described above. Starch and reducing agent can be added to such coating compositions at a variety of addition levels. For floor finish concentrates, starch preferably represents 1 to about 40 weight percent of the total concentrate weight, and preferably about 5 to about 20 weight percent. A preferred amount of reducing agent is about 1 to about 60 weight percent, more preferably about 1 to about 30 weight percent and most preferably about 1 to about 25 weight percent. For floor finish compositions diluted to use solutions (e.g., using water), a preferred starch content is about 0.1 to about 5 weight percent, more preferably about 0.5 to 2 weight percent. A preferred reducing agent content in such diluted solutions is greater than 0.2 to about 10 weight percent, more preferably about 1 to about 4 weight percent and most preferably about 1 to about 3 weight percent.
In another aspect of the invention, starch is combined with a surface cleaning composition, e.g., a floor cleaning composition, and applied to an iodine stain. Starch can be added to such surface cleaning compositions at a variety of addition levels. For floor cleaning concentrates, starch preferably represents 1 to about 40 weight percent of the total concentrate weight, and preferably about 5 to about 20 weight percent. For floor cleaning compositions diluted to use solutions (e.g., using water), a preferred starch content is about 0.1 to about 5 weight percent, more preferably about 0.5 to 2 weight percent. Formulations for suitable surface cleaning compositions will be familiar to those skilled in the art. Such compositions may contain nonionic, cationic, anionic, or amphoteric surfactants and mixtures thereof, builders (e.g., ethylene diamine tetraacetic acid (xe2x80x9cEDTAxe2x80x9d), citrate and the like), antimicrobial agents (e.g., quaternary ammonium compounds, phenolics and the like), pH modifiers (e.g., caustics, silicates, acids and the like), solvents, viscosity modifiers, anti-redeposition agents (e.g., polyacrylates and the like), and aesthetic modifiers (e.g., dyes, fragrances and the like).
In yet another aspect of the invention, starch and a reducing agent having a redox potential that will decolorize an iodine stain can be incorporated into a surface cleaning composition. The resulting composition can be used to clean an iodine-stained surface and mask the stain while decolorizing it. For surface cleaning composition concentrates, starch preferably represents 1 to about 30 weight percent of the total concentrate weight, and preferably about 5 to about 20 weight percent. A preferred amount of reducing agent is about 1 to about 50 weight percent, more preferably about 1 to about 30 weight percent and most preferably about 1 to about 25 weight percent. For surface cleaning compositions diluted to use solutions (e.g., using water), a preferred starch content is about 0.1 to about 5 weight percent, more preferably about 0.5 to 2 weight percent. A preferred reducing agent content in such diluted solutions is greater than 0.2 to about 10 weight percent, more preferably about 1 to about 4 weight percent and most preferably about 1 to about 3 weight percent.
Starch may be incorporated into the above-described compositions at any stage of the composition""s manufacture. The starch may be added as a solid, powder, crystalline material, agglomerate, or solution. Solvents (e.g., glycol ethers, alcohols, water and the like), pH modifiers (e.g., caustics, etc) or hydrotropes (e.g., sodium xylene sulfonate, potassium cumene sulfonate, octyldimethylamine oxide, monoethanolamine, diethanolamine, triethanolamine, ammonia or ammonium salts and the like) may be added if desired to assist in solubilizing or emulsifying the starch.
The compositions of the invention can also include product packaging for one-part or two-part forms of the product, instructions for use, and a suitable applicator. Such packaging can be in the form of a power pack for addition to an existing product, e.g., a floor cleaning product.
Application of a starch-containing composition of the invention to an iodine stain imparts a bluer coloration to the stain than would be obtained in the absence of starch. In a similar fashion, application of an iodine-containing product to a starch-containing composition of the invention results in a stain having less yellow coloration than would be obtained in the absence of starch. The presence of such bluer coloration can be detected using ordinary observation or using measuring instruments. The thus-masked stain does not have to be visibly blue in hue. It may in fact be white or no longer visible at all under appropriate application and viewing conditions.
The starch-containing compositions of the invention can be applied and removed using a variety of methods and devices that will be familiar to those skilled in the art. For example, such compositions may be applied using techniques such as mopping (e.g., with flat or conventional mops), spraying, wiping, autoscrubbing (e.g., using combination equipment for carrying out mechanical floor cleaning and other functions such as mechanical floor cleaning/coating or coating/burnishing equipment) or flood coating. Mop application is preferred for coating floors.
When applying starch-containing coating compositions of the invention to a substrate, the substrate typically is first cleaned and any loose debris removed. One or more coats of the coating composition (e.g., one to five coats) arc applied to the substrate, and allowed to dry. Each coat preferably will have a dry coating thickness of about 0.1 to about 100 micrometers, more preferably about 2.5 to about 20 micrometers. Preferably the overall coating thickness will be about 5 to about 150 micrometers, more preferably about 5 to about 40 micrometers. The surface of tile hardened coating composition may be renewed using techniques such as buffing/burnishing, cleaning, or by applying a suitable restorer, e.g., a floor finish restorer.
The compositions of the invention can be applied to a variety of stained or stainable surfaces including floors (e.g., in hospitals, clinics, nursing homes, doctors"" offices, dentists"" offices, veterinarians"" offices, milking parlors and the like), non-floor architectural surfaces (e.g., walls, ceilings, countertops, cabinets and the like), ambulance interiors, and fabrics (e.g., hospital linens including sheets, gowns, drapes and other textile products). The compositions of the invention can mask stains caused by procedures such as surgical scrubs, skin preparation, teat dips, and other activities where iodine-containing products are used.